net/ipv4/ipvs/ip_vs_conn.c

   1 /*
   2  * IPVS         An implementation of the IP virtual server support for the
   3  *              LINUX operating system.  IPVS is now implemented as a module
   4  *              over the Netfilter framework. IPVS can be used to build a
   5  *              high-performance and highly available server based on a
   6  *              cluster of servers.
   7  *
   8  * Version:     $Id: ip_vs_conn.c,v 1.31 2003/04/18 09:03:16 wensong Exp $
   9  *
  10  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
  11  *              Peter Kese <peter.kese@ijs.si>
  12  *              Julian Anastasov <ja@ssi.bg>
  13  *
  14  *              This program is free software; you can redistribute it and/or
  15  *              modify it under the terms of the GNU General Public License
  16  *              as published by the Free Software Foundation; either version
  17  *              2 of the License, or (at your option) any later version.
  18  *
  19  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
  20  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
  21  * and others. Many code here is taken from IP MASQ code of kernel 2.2.
  22  *
  23  * Changes:
  24  *
  25  */
  26
  27 #include <linux/interrupt.h>
  28 #include <linux/in.h>
  29 #include <linux/net.h>
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/proc_fs.h>              /* for proc_net_* */
  34 #include <linux/seq_file.h>
  35 #include <linux/jhash.h>
  36 #include <linux/random.h>
  37
  38 #include <net/net_namespace.h>
  39 #include <net/ip_vs.h>
  40
  41
  42 /*
  43  *  Connection hash table: for input and output packets lookups of IPVS
  44  */
  45 static struct list_head *ip_vs_conn_tab;
  46
  47 /*  SLAB cache for IPVS connections */
  48 static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
  49
  50 /*  counter for current IPVS connections */
  51 static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
  52
  53 /*  counter for no client port connections */
  54 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
  55
  56 /* random value for IPVS connection hash */
  57 static unsigned int ip_vs_conn_rnd;
  58
  59 /*
  60  *  Fine locking granularity for big connection hash table
  61  */
  62 #define CT_LOCKARRAY_BITS  4
  63 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
  64 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
  65
  66 struct ip_vs_aligned_lock
  67 {
  68         rwlock_t        l;
  69 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
  70
  71 /* lock array for conn table */
  72 static struct ip_vs_aligned_lock
  73 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
  74
  75 static inline void ct_read_lock(unsigned key)
  76 {
  77         read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  78 }
  79
  80 static inline void ct_read_unlock(unsigned key)
  81 {
  82         read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  83 }
  84
  85 static inline void ct_write_lock(unsigned key)
  86 {
  87         write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  88 }
  89
  90 static inline void ct_write_unlock(unsigned key)
  91 {
  92         write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  93 }
  94
  95 static inline void ct_read_lock_bh(unsigned key)
  96 {
  97         read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  98 }
  99
 100 static inline void ct_read_unlock_bh(unsigned key)
 101 {
 102         read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 103 }
 104
 105 static inline void ct_write_lock_bh(unsigned key)
 106 {
 107         write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 108 }
 109
 110 static inline void ct_write_unlock_bh(unsigned key)
 111 {
 112         write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 113 }
 114
 115
 116 /*
 117  *      Returns hash value for IPVS connection entry
 118  */
 119 static unsigned int ip_vs_conn_hashkey(unsigned proto, __be32 addr, __be16 port)
 120 {
 121         return jhash_3words((__force u32)addr, (__force u32)port, proto, ip_vs_conn_rnd)
 122                 & IP_VS_CONN_TAB_MASK;
 123 }
 124
 125
 126 /*
 127  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
 128  *      returns bool success.
 129  */
 130 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 131 {
 132         unsigned hash;
 133         int ret;
 134
 135         /* Hash by protocol, client address and port */
 136         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
 137
 138         ct_write_lock(hash);
 139
 140         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 141                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
 142                 cp->flags |= IP_VS_CONN_F_HASHED;
 143                 atomic_inc(&cp->refcnt);
 144                 ret = 1;
 145         } else {
 146                 IP_VS_ERR("ip_vs_conn_hash(): request for already hashed, "
 147                           "called from %p\n", __builtin_return_address(0));
 148                 ret = 0;
 149         }
 150
 151         ct_write_unlock(hash);
 152
 153         return ret;
 154 }
 155
 156
 157 /*
 158  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
 159  *      returns bool success.
 160  */
 161 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 162 {
 163         unsigned hash;
 164         int ret;
 165
 166         /* unhash it and decrease its reference counter */
 167         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
 168
 169         ct_write_lock(hash);
 170
 171         if (cp->flags & IP_VS_CONN_F_HASHED) {
 172                 list_del(&cp->c_list);
 173                 cp->flags &= ~IP_VS_CONN_F_HASHED;
 174                 atomic_dec(&cp->refcnt);
 175                 ret = 1;
 176         } else
 177                 ret = 0;
 178
 179         ct_write_unlock(hash);
 180
 181         return ret;
 182 }
 183
 184
 185 /*
 186  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 187  *  Called for pkts coming from OUTside-to-INside.
 188  *      s_addr, s_port: pkt source address (foreign host)
 189  *      d_addr, d_port: pkt dest address (load balancer)
 190  */
 191 static inline struct ip_vs_conn *__ip_vs_conn_in_get
 192 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 193 {
 194         unsigned hash;
 195         struct ip_vs_conn *cp;
 196
 197         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
 198
 199         ct_read_lock(hash);
 200
 201         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 202                 if (s_addr==cp->caddr && s_port==cp->cport &&
 203                     d_port==cp->vport && d_addr==cp->vaddr &&
 204                     ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 205                     protocol==cp->protocol) {
 206                         /* HIT */
 207                         atomic_inc(&cp->refcnt);
 208                         ct_read_unlock(hash);
 209                         return cp;
 210                 }
 211         }
 212
 213         ct_read_unlock(hash);
 214
 215         return NULL;
 216 }
 217
 218 struct ip_vs_conn *ip_vs_conn_in_get
 219 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 220 {
 221         struct ip_vs_conn *cp;
 222
 223         cp = __ip_vs_conn_in_get(protocol, s_addr, s_port, d_addr, d_port);
 224         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
 225                 cp = __ip_vs_conn_in_get(protocol, s_addr, 0, d_addr, d_port);
 226
 227         IP_VS_DBG(9, "lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 228                   ip_vs_proto_name(protocol),
 229                   NIPQUAD(s_addr), ntohs(s_port),
 230                   NIPQUAD(d_addr), ntohs(d_port),
 231                   cp?"hit":"not hit");
 232
 233         return cp;
 234 }
 235
 236 /* Get reference to connection template */
 237 struct ip_vs_conn *ip_vs_ct_in_get
 238 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 239 {
 240         unsigned hash;
 241         struct ip_vs_conn *cp;
 242
 243         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
 244
 245         ct_read_lock(hash);
 246
 247         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 248                 if (s_addr==cp->caddr && s_port==cp->cport &&
 249                     d_port==cp->vport && d_addr==cp->vaddr &&
 250                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
 251                     protocol==cp->protocol) {
 252                         /* HIT */
 253                         atomic_inc(&cp->refcnt);
 254                         goto out;
 255                 }
 256         }
 257         cp = NULL;
 258
 259   out:
 260         ct_read_unlock(hash);
 261
 262         IP_VS_DBG(9, "template lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 263                   ip_vs_proto_name(protocol),
 264                   NIPQUAD(s_addr), ntohs(s_port),
 265                   NIPQUAD(d_addr), ntohs(d_port),
 266                   cp?"hit":"not hit");
 267
 268         return cp;
 269 }
 270
 271 /*
 272  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 273  *  Called for pkts coming from inside-to-OUTside.
 274  *      s_addr, s_port: pkt source address (inside host)
 275  *      d_addr, d_port: pkt dest address (foreign host)
 276  */
 277 struct ip_vs_conn *ip_vs_conn_out_get
 278 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 279 {
 280         unsigned hash;
 281         struct ip_vs_conn *cp, *ret=NULL;
 282
 283         /*
 284          *      Check for "full" addressed entries
 285          */
 286         hash = ip_vs_conn_hashkey(protocol, d_addr, d_port);
 287
 288         ct_read_lock(hash);
 289
 290         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 291                 if (d_addr == cp->caddr && d_port == cp->cport &&
 292                     s_port == cp->dport && s_addr == cp->daddr &&
 293                     protocol == cp->protocol) {
 294                         /* HIT */
 295                         atomic_inc(&cp->refcnt);
 296                         ret = cp;
 297                         break;
 298                 }
 299         }
 300
 301         ct_read_unlock(hash);
 302
 303         IP_VS_DBG(9, "lookup/out %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 304                   ip_vs_proto_name(protocol),
 305                   NIPQUAD(s_addr), ntohs(s_port),
 306                   NIPQUAD(d_addr), ntohs(d_port),
 307                   ret?"hit":"not hit");
 308
 309         return ret;
 310 }
 311
 312
 313 /*
 314  *      Put back the conn and restart its timer with its timeout
 315  */
 316 void ip_vs_conn_put(struct ip_vs_conn *cp)
 317 {
 318         /* reset it expire in its timeout */
 319         mod_timer(&cp->timer, jiffies+cp->timeout);
 320
 321         __ip_vs_conn_put(cp);
 322 }
 323
 324
 325 /*
 326  *      Fill a no_client_port connection with a client port number
 327  */
 328 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
 329 {
 330         if (ip_vs_conn_unhash(cp)) {
 331                 spin_lock(&cp->lock);
 332                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 333                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 334                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 335                         cp->cport = cport;
 336                 }
 337                 spin_unlock(&cp->lock);
 338
 339                 /* hash on new dport */
 340                 ip_vs_conn_hash(cp);
 341         }
 342 }
 343
 344
 345 /*
 346  *      Bind a connection entry with the corresponding packet_xmit.
 347  *      Called by ip_vs_conn_new.
 348  */
 349 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 350 {
 351         switch (IP_VS_FWD_METHOD(cp)) {
 352         case IP_VS_CONN_F_MASQ:
 353                 cp->packet_xmit = ip_vs_nat_xmit;
 354                 break;
 355
 356         case IP_VS_CONN_F_TUNNEL:
 357                 cp->packet_xmit = ip_vs_tunnel_xmit;
 358                 break;
 359
 360         case IP_VS_CONN_F_DROUTE:
 361                 cp->packet_xmit = ip_vs_dr_xmit;
 362                 break;
 363
 364         case IP_VS_CONN_F_LOCALNODE:
 365                 cp->packet_xmit = ip_vs_null_xmit;
 366                 break;
 367
 368         case IP_VS_CONN_F_BYPASS:
 369                 cp->packet_xmit = ip_vs_bypass_xmit;
 370                 break;
 371         }
 372 }
 373
 374
 375 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 376 {
 377         return atomic_read(&dest->activeconns)
 378                 + atomic_read(&dest->inactconns);
 379 }
 380
 381 /*
 382  *      Bind a connection entry with a virtual service destination
 383  *      Called just after a new connection entry is created.
 384  */
 385 static inline void
 386 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 387 {
 388         /* if dest is NULL, then return directly */
 389         if (!dest)
 390                 return;
 391
 392         /* Increase the refcnt counter of the dest */
 393         atomic_inc(&dest->refcnt);
 394
 395         /* Bind with the destination and its corresponding transmitter */
 396         cp->flags |= atomic_read(&dest->conn_flags);
 397         cp->dest = dest;
 398
 399         IP_VS_DBG(7, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 400                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 401                   "dest->refcnt:%d\n",
 402                   ip_vs_proto_name(cp->protocol),
 403                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 404                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 405                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 406                   ip_vs_fwd_tag(cp), cp->state,
 407                   cp->flags, atomic_read(&cp->refcnt),
 408                   atomic_read(&dest->refcnt));
 409
 410         /* Update the connection counters */
 411         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 412                 /* It is a normal connection, so increase the inactive
 413                    connection counter because it is in TCP SYNRECV
 414                    state (inactive) or other protocol inacive state */
 415                 atomic_inc(&dest->inactconns);
 416         } else {
 417                 /* It is a persistent connection/template, so increase
 418                    the peristent connection counter */
 419                 atomic_inc(&dest->persistconns);
 420         }
 421
 422         if (dest->u_threshold != 0 &&
 423             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 424                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 425 }
 426
 427
 428 /*
 429  *      Unbind a connection entry with its VS destination
 430  *      Called by the ip_vs_conn_expire function.
 431  */
 432 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 433 {
 434         struct ip_vs_dest *dest = cp->dest;
 435
 436         if (!dest)
 437                 return;
 438
 439         IP_VS_DBG(7, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 440                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 441                   "dest->refcnt:%d\n",
 442                   ip_vs_proto_name(cp->protocol),
 443                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 444                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 445                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 446                   ip_vs_fwd_tag(cp), cp->state,
 447                   cp->flags, atomic_read(&cp->refcnt),
 448                   atomic_read(&dest->refcnt));
 449
 450         /* Update the connection counters */
 451         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 452                 /* It is a normal connection, so decrease the inactconns
 453                    or activeconns counter */
 454                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 455                         atomic_dec(&dest->inactconns);
 456                 } else {
 457                         atomic_dec(&dest->activeconns);
 458                 }
 459         } else {
 460                 /* It is a persistent connection/template, so decrease
 461                    the peristent connection counter */
 462                 atomic_dec(&dest->persistconns);
 463         }
 464
 465         if (dest->l_threshold != 0) {
 466                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 467                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 468         } else if (dest->u_threshold != 0) {
 469                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 470                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 471         } else {
 472                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 473                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 474         }
 475
 476         /*
 477          * Simply decrease the refcnt of the dest, because the
 478          * dest will be either in service's destination list
 479          * or in the trash.
 480          */
 481         atomic_dec(&dest->refcnt);
 482 }
 483
 484
 485 /*
 486  *      Checking if the destination of a connection template is available.
 487  *      If available, return 1, otherwise invalidate this connection
 488  *      template and return 0.
 489  */
 490 int ip_vs_check_template(struct ip_vs_conn *ct)
 491 {
 492         struct ip_vs_dest *dest = ct->dest;
 493
 494         /*
 495          * Checking the dest server status.
 496          */
 497         if ((dest == NULL) ||
 498             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 499             (sysctl_ip_vs_expire_quiescent_template &&
 500              (atomic_read(&dest->weight) == 0))) {
 501                 IP_VS_DBG(9, "check_template: dest not available for "
 502                           "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 503                           "-> d:%u.%u.%u.%u:%d\n",
 504                           ip_vs_proto_name(ct->protocol),
 505                           NIPQUAD(ct->caddr), ntohs(ct->cport),
 506                           NIPQUAD(ct->vaddr), ntohs(ct->vport),
 507                           NIPQUAD(ct->daddr), ntohs(ct->dport));
 508
 509                 /*
 510                  * Invalidate the connection template
 511                  */
 512                 if (ct->vport != htons(0xffff)) {
 513                         if (ip_vs_conn_unhash(ct)) {
 514                                 ct->dport = htons(0xffff);
 515                                 ct->vport = htons(0xffff);
 516                                 ct->cport = 0;
 517                                 ip_vs_conn_hash(ct);
 518                         }
 519                 }
 520
 521                 /*
 522                  * Simply decrease the refcnt of the template,
 523                  * don't restart its timer.
 524                  */
 525                 atomic_dec(&ct->refcnt);
 526                 return 0;
 527         }
 528         return 1;
 529 }
 530
 531 static void ip_vs_conn_expire(unsigned long data)
 532 {
 533         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 534
 535         cp->timeout = 60*HZ;
 536
 537         /*
 538          *      hey, I'm using it
 539          */
 540         atomic_inc(&cp->refcnt);
 541
 542         /*
 543          *      do I control anybody?
 544          */
 545         if (atomic_read(&cp->n_control))
 546                 goto expire_later;
 547
 548         /*
 549          *      unhash it if it is hashed in the conn table
 550          */
 551         if (!ip_vs_conn_unhash(cp))
 552                 goto expire_later;
 553
 554         /*
 555          *      refcnt==1 implies I'm the only one referrer
 556          */
 557         if (likely(atomic_read(&cp->refcnt) == 1)) {
 558                 /* delete the timer if it is activated by other users */
 559                 if (timer_pending(&cp->timer))
 560                         del_timer(&cp->timer);
 561
 562                 /* does anybody control me? */
 563                 if (cp->control)
 564                         ip_vs_control_del(cp);
 565
 566                 if (unlikely(cp->app != NULL))
 567                         ip_vs_unbind_app(cp);
 568                 ip_vs_unbind_dest(cp);
 569                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 570                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 571                 atomic_dec(&ip_vs_conn_count);
 572
 573                 kmem_cache_free(ip_vs_conn_cachep, cp);
 574                 return;
 575         }
 576
 577         /* hash it back to the table */
 578         ip_vs_conn_hash(cp);
 579
 580   expire_later:
 581         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 582                   atomic_read(&cp->refcnt)-1,
 583                   atomic_read(&cp->n_control));
 584
 585         ip_vs_conn_put(cp);
 586 }
 587
 588
 589 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 590 {
 591         if (del_timer(&cp->timer))
 592                 mod_timer(&cp->timer, jiffies);
 593 }
 594
 595
 596 /*
 597  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 598  */
 599 struct ip_vs_conn *
 600 ip_vs_conn_new(int proto, __be32 caddr, __be16 cport, __be32 vaddr, __be16 vport,
 601                __be32 daddr, __be16 dport, unsigned flags,
 602                struct ip_vs_dest *dest)
 603 {
 604         struct ip_vs_conn *cp;
 605         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 606
 607         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 608         if (cp == NULL) {
 609                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
 610                 return NULL;
 611         }
 612
 613         INIT_LIST_HEAD(&cp->c_list);
 614         init_timer(&cp->timer);
 615         cp->timer.data     = (unsigned long)cp;
 616         cp->timer.function = ip_vs_conn_expire;
 617         cp->protocol       = proto;
 618         cp->caddr          = caddr;
 619         cp->cport          = cport;
 620         cp->vaddr          = vaddr;
 621         cp->vport          = vport;
 622         cp->daddr          = daddr;
 623         cp->dport          = dport;
 624         cp->flags          = flags;
 625         spin_lock_init(&cp->lock);
 626
 627         /*
 628          * Set the entry is referenced by the current thread before hashing
 629          * it in the table, so that other thread run ip_vs_random_dropentry
 630          * but cannot drop this entry.
 631          */
 632         atomic_set(&cp->refcnt, 1);
 633
 634         atomic_set(&cp->n_control, 0);
 635         atomic_set(&cp->in_pkts, 0);
 636
 637         atomic_inc(&ip_vs_conn_count);
 638         if (flags & IP_VS_CONN_F_NO_CPORT)
 639                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 640
 641         /* Bind the connection with a destination server */
 642         ip_vs_bind_dest(cp, dest);
 643
 644         /* Set its state and timeout */
 645         cp->state = 0;
 646         cp->timeout = 3*HZ;
 647
 648         /* Bind its packet transmitter */
 649         ip_vs_bind_xmit(cp);
 650
 651         if (unlikely(pp && atomic_read(&pp->appcnt)))
 652                 ip_vs_bind_app(cp, pp);
 653
 654         /* Hash it in the ip_vs_conn_tab finally */
 655         ip_vs_conn_hash(cp);
 656
 657         return cp;
 658 }
 659
 660
 661 /*
 662  *      /proc/net/ip_vs_conn entries
 663  */
 664 #ifdef CONFIG_PROC_FS
 665
 666 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 667 {
 668         int idx;
 669         struct ip_vs_conn *cp;
 670
 671         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 672                 ct_read_lock_bh(idx);
 673                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 674                         if (pos-- == 0) {
 675                                 seq->private = &ip_vs_conn_tab[idx];
 676                                 return cp;
 677                         }
 678                 }
 679                 ct_read_unlock_bh(idx);
 680         }
 681
 682         return NULL;
 683 }
 684
 685 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 686 {
 687         seq->private = NULL;
 688         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 689 }
 690
 691 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 692 {
 693         struct ip_vs_conn *cp = v;
 694         struct list_head *e, *l = seq->private;
 695         int idx;
 696
 697         ++*pos;
 698         if (v == SEQ_START_TOKEN)
 699                 return ip_vs_conn_array(seq, 0);
 700
 701         /* more on same hash chain? */
 702         if ((e = cp->c_list.next) != l)
 703                 return list_entry(e, struct ip_vs_conn, c_list);
 704
 705         idx = l - ip_vs_conn_tab;
 706         ct_read_unlock_bh(idx);
 707
 708         while (++idx < IP_VS_CONN_TAB_SIZE) {
 709                 ct_read_lock_bh(idx);
 710                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 711                         seq->private = &ip_vs_conn_tab[idx];
 712                         return cp;
 713                 }
 714                 ct_read_unlock_bh(idx);
 715         }
 716         seq->private = NULL;
 717         return NULL;
 718 }
 719
 720 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 721 {
 722         struct list_head *l = seq->private;
 723
 724         if (l)
 725                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 726 }
 727
 728 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 729 {
 730
 731         if (v == SEQ_START_TOKEN)
 732                 seq_puts(seq,
 733    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 734         else {
 735                 const struct ip_vs_conn *cp = v;
 736
 737                 seq_printf(seq,
 738                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
 739                                 ip_vs_proto_name(cp->protocol),
 740                                 ntohl(cp->caddr), ntohs(cp->cport),
 741                                 ntohl(cp->vaddr), ntohs(cp->vport),
 742                                 ntohl(cp->daddr), ntohs(cp->dport),
 743                                 ip_vs_state_name(cp->protocol, cp->state),
 744                                 (cp->timer.expires-jiffies)/HZ);
 745         }
 746         return 0;
 747 }
 748
 749 static const struct seq_operations ip_vs_conn_seq_ops = {
 750         .start = ip_vs_conn_seq_start,
 751         .next  = ip_vs_conn_seq_next,
 752         .stop  = ip_vs_conn_seq_stop,
 753         .show  = ip_vs_conn_seq_show,
 754 };
 755
 756 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 757 {
 758         return seq_open(file, &ip_vs_conn_seq_ops);
 759 }
 760
 761 static const struct file_operations ip_vs_conn_fops = {
 762         .owner   = THIS_MODULE,
 763         .open    = ip_vs_conn_open,
 764         .read    = seq_read,
 765         .llseek  = seq_lseek,
 766         .release = seq_release,
 767 };
 768 #endif
 769
 770
 771 /*
 772  *      Randomly drop connection entries before running out of memory
 773  */
 774 static inline int todrop_entry(struct ip_vs_conn *cp)
 775 {
 776         /*
 777          * The drop rate array needs tuning for real environments.
 778          * Called from timer bh only => no locking
 779          */
 780         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 781         static char todrop_counter[9] = {0};
 782         int i;
 783
 784         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 785            This will leave enough time for normal connection to get
 786            through. */
 787         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 788                 return 0;
 789
 790         /* Don't drop the entry if its number of incoming packets is not
 791            located in [0, 8] */
 792         i = atomic_read(&cp->in_pkts);
 793         if (i > 8 || i < 0) return 0;
 794
 795         if (!todrop_rate[i]) return 0;
 796         if (--todrop_counter[i] > 0) return 0;
 797
 798         todrop_counter[i] = todrop_rate[i];
 799         return 1;
 800 }
 801
 802 /* Called from keventd and must protect itself from softirqs */
 803 void ip_vs_random_dropentry(void)
 804 {
 805         int idx;
 806         struct ip_vs_conn *cp;
 807
 808         /*
 809          * Randomly scan 1/32 of the whole table every second
 810          */
 811         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
 812                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
 813
 814                 /*
 815                  *  Lock is actually needed in this loop.
 816                  */
 817                 ct_write_lock_bh(hash);
 818
 819                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 820                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
 821                                 /* connection template */
 822                                 continue;
 823
 824                         if (cp->protocol == IPPROTO_TCP) {
 825                                 switch(cp->state) {
 826                                 case IP_VS_TCP_S_SYN_RECV:
 827                                 case IP_VS_TCP_S_SYNACK:
 828                                         break;
 829
 830                                 case IP_VS_TCP_S_ESTABLISHED:
 831                                         if (todrop_entry(cp))
 832                                                 break;
 833                                         continue;
 834
 835                                 default:
 836                                         continue;
 837                                 }
 838                         } else {
 839                                 if (!todrop_entry(cp))
 840                                         continue;
 841                         }
 842
 843                         IP_VS_DBG(4, "del connection\n");
 844                         ip_vs_conn_expire_now(cp);
 845                         if (cp->control) {
 846                                 IP_VS_DBG(4, "del conn template\n");
 847                                 ip_vs_conn_expire_now(cp->control);
 848                         }
 849                 }
 850                 ct_write_unlock_bh(hash);
 851         }
 852 }
 853
 854
 855 /*
 856  *      Flush all the connection entries in the ip_vs_conn_tab
 857  */
 858 static void ip_vs_conn_flush(void)
 859 {
 860         int idx;
 861         struct ip_vs_conn *cp;
 862
 863   flush_again:
 864         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
 865                 /*
 866                  *  Lock is actually needed in this loop.
 867                  */
 868                 ct_write_lock_bh(idx);
 869
 870                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 871
 872                         IP_VS_DBG(4, "del connection\n");
 873                         ip_vs_conn_expire_now(cp);
 874                         if (cp->control) {
 875                                 IP_VS_DBG(4, "del conn template\n");
 876                                 ip_vs_conn_expire_now(cp->control);
 877                         }
 878                 }
 879                 ct_write_unlock_bh(idx);
 880         }
 881
 882         /* the counter may be not NULL, because maybe some conn entries
 883            are run by slow timer handler or unhashed but still referred */
 884         if (atomic_read(&ip_vs_conn_count) != 0) {
 885                 schedule();
 886                 goto flush_again;
 887         }
 888 }
 889
 890
 891 int ip_vs_conn_init(void)
 892 {
 893         int idx;
 894
 895         /*
 896          * Allocate the connection hash table and initialize its list heads
 897          */
 898         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
 899         if (!ip_vs_conn_tab)
 900                 return -ENOMEM;
 901
 902         /* Allocate ip_vs_conn slab cache */
 903         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
 904                                               sizeof(struct ip_vs_conn), 0,
 905                                               SLAB_HWCACHE_ALIGN, NULL);
 906         if (!ip_vs_conn_cachep) {
 907                 vfree(ip_vs_conn_tab);
 908                 return -ENOMEM;
 909         }
 910
 911         IP_VS_INFO("Connection hash table configured "
 912                    "(size=%d, memory=%ldKbytes)\n",
 913                    IP_VS_CONN_TAB_SIZE,
 914                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
 915         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
 916                   sizeof(struct ip_vs_conn));
 917
 918         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 919                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
 920         }
 921
 922         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
 923                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
 924         }
 925
 926         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
 927
 928         /* calculate the random value for connection hash */
 929         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
 930
 931         return 0;
 932 }
 933
 934
 935 void ip_vs_conn_cleanup(void)
 936 {
 937         /* flush all the connection entries first */
 938         ip_vs_conn_flush();
 939
 940         /* Release the empty cache */
 941         kmem_cache_destroy(ip_vs_conn_cachep);
 942         proc_net_remove(&init_net, "ip_vs_conn");
 943         vfree(ip_vs_conn_tab);
 944 }